The use of thermosetting resins or reactants to impart crease resistance and dimensional stability to textile materials is well-known in the art. These materials, known as "aminoplast resins," include the products of the reaction of formaldehyde with such compounds as urea, thiourea, ethylene urea, dihydroxyethylene urea, melamines, or the like. A serious drawback to the use of such materials is that they contain free formaldehyde. This is present during the preparation and storage of the finishing agent and its use in treating textiles, on the treated fabric, and on the finished garments. Also, when the fabrics or garments made therefrom are stored under humid conditions, additional free formaldehyde is produced.
The presence of even less than one percent of free formaldehyde, based on the total weight of the product, is undesirable, not only because of its unpleasant odor, but because it is an allergen and an irritant, causing severe reactions in the operators who manufacture the agent and who treat and handle the treated fabrics and to persons who handle and wear garments fabricated from the treated fabrics.
These problems associated with the presence of free formaldehyde on treated fabrics are well-known, and considerable efforts have been made to produce formaldehyde-free textile fabrics. One solution to the problem has been to employ scavengers for the free formaldehyde. In U.S. Pat. No. 3,590,100 cylic ethylene urea and propylene urea are disclosed in scavengers. Removal of the formaldehyde by reaction with phthalimide is disclosed in U.S. Pat. No. 3,723,058, and 4,127,382 teaches certain nitrogen-containing heterocyclic compounds as scavengers.
Treating textiles with resin compositions that do not contain or evolve formaldehyde is also known, as in U.S. Pat. No. 3,260,565, which teaches finishing agents formed by the reaction of alkyl or aryl ureas or thioureas with glyoxal. These agents, however, have the disadvantage of having marginal permanent press properties.